1,545 research outputs found
Support Vector Machine in Prediction of Building Energy Demand Using Pseudo Dynamic Approach
Building's energy consumption prediction is a major concern in the recent
years and many efforts have been achieved in order to improve the energy
management of buildings. In particular, the prediction of energy consumption in
building is essential for the energy operator to build an optimal operating
strategy, which could be integrated to building's energy management system
(BEMS). This paper proposes a prediction model for building energy consumption
using support vector machine (SVM). Data-driven model, for instance, SVM is
very sensitive to the selection of training data. Thus the relevant days data
selection method based on Dynamic Time Warping is used to train SVM model. In
addition, to encompass thermal inertia of building, pseudo dynamic model is
applied since it takes into account information of transition of energy
consumption effects and occupancy profile. Relevant days data selection and
whole training data model is applied to the case studies of Ecole des Mines de
Nantes, France Office building. The results showed that support vector machine
based on relevant data selection method is able to predict the energy
consumption of building with a high accuracy in compare to whole data training.
In addition, relevant data selection method is computationally cheaper (around
8 minute training time) in contrast to whole data training (around 31 hour for
weekend and 116 hour for working days) and reveals realistic control
implementation for online system as well.Comment: Proceedings of ECOS 2015-The 28th International Conference on
Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy
Systems , Jun 2015, Pau, Franc
Reversible spin texture in ferroelectric HfO\u3csub\u3e2\u3c/sub\u3e
Spin-orbit coupling effects occurring in noncentrosymmetric materials are known to be responsible for nontrivial spin configurations and a number of emergent physical phenomena. Ferroelectric materials may be especially interesting in this regard due to reversible spontaneous polarization making possible a nonvolatile electrical control of the spin degrees of freedom. Here, we explore a technologically relevant oxide material, HfO2, which has been shown to exhibit robust ferroelectricity in a noncentrosymmetric orthorhombic phase. Using theoretical modelling based on density-functional theory, we investigate the spin-dependent electronic structure of the ferroelectric HfO2 and demonstrate the appearance of chiral spin textures driven by spin-orbit coupling. We analyze these spin configurations in terms of the Rashba and Dresselhaus effects within the k · p Hamiltonian model and find that the Rashba-type spin texture dominates around the valence-band maximum, while the Dresselhaus-type spin texture prevails around the conduction band minimum. The latter is characterized by a very large Dresselhaus constant λD = 0.578 eV A, which allows using this material as a tunnel barrier to ˚ produce tunneling anomalous and spin Hall effects that are reversible by ferroelectric polarization
Human Appropriation of Net Primary Production: From a Planet to a Pixel
Human appropriation of net primary production (HANPP) is a substantial improvement upon 20th century attempts at developing an ecological footprint indicator because of its measurability in relation to net primary production, its close relationship to other key footprint measures, such as carbon and water, and its spatial specificity. This paper explores HANPP across four geographical scales: through literature review, the planet; through reanalysis of existing data, variations among the world’s countries; and through novel analyses, U.S. counties and the 30 m pixel scale for one U.S. county. Results show that HANPP informs different sustainability narratives at different scales. At the planetary scale, HANPP is a critical planetary limit that improves upon areal land use indicators. At the country macroscale, HANPP indicates the degree to which meeting the needs of the domestic population for provisioning ecosystem services (food, feed, biofiber, biofuel) presses against the domestic ecological endowment of net primary production. At the county mesoscale, HANPP reveals the dependency of metropolitan areas upon regional specialized rural forestry and agroecosystems to which they are teleconnected through trade and transport infrastructures. At the pixel microscale, HANPP provides the basis for deriving spatial patterns of remaining net primary production upon which biodiversity and regulatory and cultural ecosystem services are dependent. HANPP is thus a sustainability indicator that can fulfill similar needs as carbon, water and other footprints
Reversible spin texture in ferroelectric HfO2
Spin-orbit coupling effects occurring in non-centrosymmetric materials are
known to be responsible for non-trivial spin configurations and a number of
emergent physical phenomena. Ferroelectric materials may be especially
interesting in this regard due to reversible spontaneous polarization making
possible for a non-volatile electrical control of the spin degrees of freedom.
Here, we explore a technologically relevant oxide material, HfO2, which has
been shown to exhibit robust ferroelectricity in a non-centrosymmetric
orthorhombic phase. Using theoretical modelling based on density-functional
theory, we investigate the spin-dependent electronic structure of the
ferroelectric HfO2 and demonstrate the appearance of chiral spin textures
driven by spin-orbit coupling. We analyze these spin configurations in terms of
the Rashba and Dresselhaus effects within the k.p Hamiltonian model and find
that the Rashba-type spin texture dominates around the valence band maximum,
while the Dresselhaus-type spin texture prevails around the conduction band
minimum. The latter is characterized by a very large Dresselhaus constant
{\alpha}D = 0.578 eV {\AA}, which allows using this material as a tunnel
barrier to produce tunneling anomalous and spin Hall effects that are
reversible by ferroelectric polarization
On the saturations of submodules
Let R ⊆ S be a ring extension, and let A be an R-submodule of S. The saturation of A (in S) by τ is set A[τ] = {x ∈ S : tx ∈ A for some t ∈ τ}, where τ is a multiplicative subset of R. We study properties of saturations of R-submodules of S. We use this notion of saturation to characterize star operations ⋆ on ring extensions R ⊆ S satisfying the relation (A ∩ B)⋆ = A⋆ ∩ B⋆ whenever A and B are two R-submodules of S such that AS = BS = S
Extrapulmonary Tuberculosis: A retrospective Study at a tertiary care hospital in Palpa, Nepal
Background: Extra-pulmonary tuberculosis (EPTB) is a significant global health problem. Related studies to it in different places and diff erent durations are indicated by many previous research findings. Findings of this study could be beneficial for its preventive and control strategies. Methodology: Retrospective analysis of clinical specimens submitted to Central laboratory of Lumbini Medical College and Teaching Hospital (LMCTH) for extrapulmonary tuberculosis was performed. Total 261 samples submitted from April 2011 to February 2013 were included for analysis in this study. Results: Total 20.7% (54/261) prevalence of EPTB was reported. Based on sites involved; lymph node 87.03%, pleural effusion7.40%, peritoneal5.55% were found. Genderwise equal prevalence was seen among male and females. Age-wise prevalence among patients between 21-40 years was reported. Conclusion: Our finding indicates great necessity for further large scale study on prevalence of EPTB in this location for its prevention and control
Confirmatory factor analysis of the Pittsburgh Sleep Quality Index in women with hot flashes
OBJECTIVE: Women, especially those with hot flashes, report poor sleep quality during various stages of the menopausal transition and postmenopause. Sleep measurements vary widely because of the copious instruments available. The Pittsburgh Sleep Quality Index (PSQI) is a frequently used questionnaire that produces a single score for sleep quality. This one-factor structure has not received consistent support in the literature. The goal of this analysis was to determine the best factor structure of the PSQI in women with hot flashes.
METHODS: A confirmatory factor analysis was conducted on PSQI baseline data from three randomized controlled clinical trials enrolling perimenopausal and postmenopausal women with hot flashes (N = 849) from the Menopause Strategies: Finding Lasting Answers for Symptoms and Health network. Several a priori factor models were compared.
RESULTS: One-factor and two-factor models did not fit the data. A three-factor model comprising sleep efficiency, perceived sleep quality, and daily disturbance showed good fit; however, the sleep medication item was dropped because of poor fit and low rates of sleep medication use. The three-factor model was examined in African-American and white subsamples and was found to be similar in both groups; however, two items showed small group differences in strength as indicators.
CONCLUSIONS: Sleep quality in midlife women with hot flashes, as measured by the PSQI, seems to comprise three correlated factors. Minor measurement differences detected between groups are of research interest but do not necessitate different scoring practices. Additional research is needed to further define sleep quality and its associations with health-related outcomes
Allocation of U.S. Biomass Production to Food, Feed, Fiber, Fuel and Exports
This paper analyzes the end uses—food, feed, fiber, fuel, and exports—of biomass production in the U.S. in 1997, 2002, 2007, and 2012. They are also analyzed at the state level in 2012. Biomass production is measured as human appropriation of net primary production (HANPP), an ecological footprint measured as carbon fixed through photosynthesis, derived from data on crop, timber and grazing yields. HANPP was allocated to end uses using publicly available sources from the U.S. Department of Agriculture and internet-based sources publishing data on agricultural trade. HANPP was 717–834 megatons (MT) of carbon per year, which comprised 515–615 MT of crop-based, 105–149 MT timber-based, and 64–76 MT of grazed HANPP. Livestock feed commanded the largest proportion, but decreased from 395 (50%) to 305 MT (42%) of all HANPP and 320 to 240 MT (58–44%) of crop-based HANPP. The proportion allocated to exports was stable at 118–141 MT (17–18%) of total HANPP and 112–133 MT (21–23%) of crop-based HANPP. Biofiber decreased from 141 MT (18%) to 97 MT (13%) of all HANPP. Biofuel increased strongly from 11 MT to 98 MT, from 1% to 14% of all HANPP and 2% to 18% of crop-based HANPP, surpassing food and biofiber by 2012. Direct food commanded 89–105 MT, the lowest proportion at 12–13% of all HANPP, and 17–18% of crop-based HANPP. The highly fertile Midwest and the drought-prone Intermountain West stand out as regions where a very small percentage of biomass is allocated to direct human food. The high proportions of biomass production allocated to nonfood uses is consistent with the tragedy of ecosystem services and commodification of nature frameworks. Reducing these proportions presents opportunities for improving ecosystem services, food security, and human well-being
Quantification of anandamide, oleoylethanolamide and palmitoylethanolamide in rodent brain tissue using high performance liquid chromatography–electrospray mass spectroscopy
AbstractReported concentrations for endocannabinoids and related lipids in biological tissues can vary greatly; therefore, methods used to quantify these compounds need to be validated. This report describes a method to quantify anandamide (AEA), oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) from rodent brain tissue. Analytes were extracted using acetonitrile without further sample clean up, resolved on a C18 reverse-phase column using a gradient mobile phase and detected using electrospray ionization in positive selected ion monitoring mode on a single quadrupole mass spectrometer. The method produced high recovery rates for AEA, OEA and PEA, ranging from 98.1% to 106.2%, 98.5% to 102.2% and 85.4% to 89.5%, respectively. The method resulted in adequate sensitivity with a lower limit of quantification for AEA, OEA and PEA of 1.4ng/mL, 0.6ng/mL and 0.5ng/mL, respectively. The method was reproducible as intraday and interday accuracies and precisions were under 15%. This method was suitable for quantifying AEA, OEA and PEA from rat brain following pharmacological inhibition of fatty acid amide hydrolase
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